Overriding the radical polarity matching principle: selective chlorohydroxylation of electron-deficient alkenes enabled by Ce photocatalysis.

Radical addition to alkenes generally follows the polarity matching principle; for instance, the electrophilic chlorine radical favors electron-rich double bonds over electron-deficient ones in alkenes. Herein, we achieve a one-step selective aerobic chlorohydroxylation of alkenes via Ce-LMCT-generated chlorine radicals. The protocol exhibits a broad substrate scope, notably extending to electron-deficient, amide-containing alkenes-a class of substrates historically challenging for the addition of electrophilic radicals due to the polarity matching principle. Theoretical calculations reveal that the radical adduct generated from the chlorine radical and amide-containing alkene is stabilized by the amide group, which helps the system to override the radical polarity matching principle.